Short answer: 65–75°F water wants a 3/2. 58–65°F wants a 4/3. 50–58°F wants a 5/3 with boots and a hood. Below 50°F, a 5/3 or a 6/4/3 hooded double front-zip plus 5–7mm boots, hood and gloves. Above 75°F, a shorty, a top, or boardshorts. Those are the bands our gear advisor uses, and they are water temperature, not air.
The band table
| Water temperature | What to wear | Extras |
|---|---|---|
| 75°F and up | Shorty, top, or boardshorts | — |
| 65–75°F | 3/2 fullsuit | — |
| 58–65°F | 4/3 fullsuit | Boots on the cold end |
| 50–58°F | 5/3 fullsuit | Boots and hood |
| Below 50°F | 5/3, or a 6/4/3 hooded double front-zip | 5–7mm boots, hood, gloves |
What the two numbers mean
A 4/3 is 4mm neoprene over the torso and 3mm in the arms and legs. Thicker where you lose the most heat, thinner where you need to bend. A 6/4/3 is the same idea with three zones — 6mm chest, 4mm mid, 3mm limbs — which is how a suit stays warm enough for sub-50°F water without turning your shoulders into cardboard. The first number is always the warmth number; the last number is always the mobility number.
Air temperature is the second number
The bands above are water. Kiting and winging are the two sports where that is not the whole story, because you spend most of the session out of the water and in the wind. A 60°F day on 66°F water will feel colder on a kite than the same water feels to a surfer sitting in it. If the air is cold, the wind is strong, or the session is long, take the next step up. Nobody has ever cut a session short because their suit was slightly too warm.
Then the size chart
Thickness first, fit second — and fit matters more in a wetsuit than in almost anything else you own, because a loose suit flushes cold water through itself all session. Mystic sizes on height, chest and waist together. Part of the men's/unisex chart, printed as Mystic publishes it:
| Size | Height | Chest | Waist |
|---|---|---|---|
| S | 5'7"–5'9" | 35"–37" | 29"–31" |
| M | 5'9"–5'11" | 37"–39" | 31"–33" |
| L | 5'11"–6'2" | 39"–41" | 33"–35" |
| XL | 6'1"–6'4" | 41"–44" | 35"–38" |
| XXL | 6'2"–6'5" | 44"–47" | 38"–41" |
Mystic also publishes the letters most people miss: ST, MT, LT and XLT are tall cuts — same chest and waist, two to four inches more height — and MS and LS are the short-wide cuts. If you are 6'2" with a 38" chest, LT is your suit and L is not. The complete men's, women's and junior charts are on the wetsuit sizing page.
Honest limit: a temperature band is a starting point, not a prescription. People run warm and cold by a solid five degrees in either direction, thin riders chill faster than the chart expects, and a suit's seams and lining change how warm the same millimetres feel — a taped, lined 4/3 beats a flatlock 5/3 in real water. Treat the band as the thickness to start from, then adjust one step for how you personally handle cold and how long your sessions run. We do size exchanges on unworn waterwear, so getting the fit right on the second try costs you nothing but the wait.
What to buy in each band
As of this post, across the Mystic suits we have in stock:
- 3/2 (65–75°F): adult fullsuits from about $168 for the Brand 3/2 Bzip to about $517 for the Majestic 3/2 Fzip; shorties from about $120.
- 4/3 (58–65°F): the Star Fullsuit 4/3 Bzip 2025 at about $288, the Motion 4/3 Fzip at about $348, up to the Majestic at about $528.
- 5/3 (50–58°F): from about $260 for the Star 5/3 Bzip to about $539 for the Majestic 5/3 Fzip 2026; the Motion 5/3 Fzip sits in the middle at about $360, and there is a hooded version at about $396.
- Below 50°F: hooded 6/4/3 double front-zip suits, about $570–$590, plus boots, gloves and a hood from the hoods, gloves and boots collection.
The whole range is in wetsuits, and US orders over $100 ship free. Not sure between two thicknesses or two sizes? Give your height, chest, waist and your home water temperature to the gear advisor.
FAQ
What wetsuit thickness for 60 degree water?
A 4/3. Sixty degrees sits in the middle of the 58–65°F band. Add boots if the air is cold or the session is long, and step up to a 5/3 if you are riding through the bottom of that band regularly.
Is a 4/3 or a 5/4 warmer?
The 5/4 — one more millimetre on the torso and on the limbs. It is also stiffer and slower to dry. A 5/4 or 5/3 is the 50–58°F suit; a 4/3 is the 58–65°F suit.
Should a wetsuit be tight?
Snug everywhere, with no loose pockets at the lower back, behind the knees or in the armpits, and no gap at the neck. It should be hard to put on dry and comfortable once it is wet. Water sitting in a loose panel is what makes a suit cold, not the millimetre rating.